At present, an annular component such as a large size bearing of a wind turbine is normally assembled to a component such as a motor shaft via a shrink fit mounting method. The shrink fit mounting method means that a bearing is heated in a hot liquid or a hot gas before mounting, and an inner diameter of the bearing is enlarged based on thermal expansion and contraction principle. The expanded bearing can be mounted to the motor shaft, and the bearing will be fixed to the motor shaft after being cooled. The bearing is generally heated in a heating furnace, and air is typically used as a heat exchange medium in the heating furnace. A specific structure of the heating furnace in prior art is provided hereinafter.
The heating furnace includes a furnace body. A blower (such as a fan) unit, a heating component, and a support component are arranged in the furnace body. The blower unit typically has a centrifugal fan and a motor for rotating the centrifugal fan. The blower unit is mainly used to drive air to circulate in the furnace body, the heating component is used to heat the air circulating in the furnace body, and the support component is mainly used to support bearings. Since a large size bearing has a relatively large inner diameter, the space enclosed by the inner diameter is relatively large, and the flow area is relatively large accordingly. The larger the flow area is, the greater the power of the motor in a corresponding fan unit is, and the higher the energy consumption per unit time is.
In order to reduce energy consumption as much as possible, an adiabatic sealed cylinder is further arranged in the inner chamber of the bearing. The adiabatic sealed cylinder is used to enclose an inner ring space of the bearing parts under the centrifugal fan and far away from a heated surface of the conventional heating furnace plus a negative pressurized convergence space after air sweeping across the bearing. A cylindrical adiabatic sealed chamber is arranged in the center of the furnace by using the space, meanwhile, the chamber acts as an airflow accumulated “pressure forebay” for guiding and blowing device for heated surfaces of large size bearings and as a necessary structural link to obtain the inlet airflow guiding and acceleration of the high speed airflow “homogenization” blowing device, limits all of the “flowing airflow” being converted into “effective heat exchange airflow” to the heat exchange space on the bearing surface. The effective heat exchange gas flow refers to: the flowing gas flow driven by the centrifugal fan is all limited to contact and impact a lower surface, an outer surface, an inner surface, and sweep across an upper surface. The gas flow all participates in heat exchange, and converges at a suction inlet of the centrifugal fan. Thus the volume of the effective space is greatly reduced, the ratio of the centrifugal fan driving power to the “effective heat exchange gas flow” velocity is greatly decreased, and the heat exchange rate is greatly improved.
However, it is found in the practical using processes that, the heating efficiency varies greatly according to the size of the bearings heated in the heating furnace equipped with the cylindrical adiabatic sealed chamber, the heating efficiency of the bearings with a large diameter is relatively higher, and the heating efficiency of the bearings with a relatively small diameter and a thick wall is lower, that is, the cylindrical adiabatic sealed chamber cannot play its role.
In addition, as the adiabatic sealed chamber is arranged in the central region of the annular component with a large diameter, which occupies larger radial space of the heating furnace body, the overall radial size of the device body will be too large and the overall radial size may even exceeds the allowed width of transportation, which brings great difficulties for transportation and mobile plant using.
Therefore, an issue to be addressed presently by the person skilled in the art is how to solve the technical problems mentioned above.